Cannot set local IP on my interfase!

I have a RB1100Hx2 and it is in router mode.
in quick set windows I can set ip address for internet ip address to access it via internet which is my ether1.

then for my ether2 i set ip address 20.20.20.1/24

and for ether3 i set ip address 192.168.168.1/24

problem is i want my local ip in quick set window set to 20.20.20.1 which is my ether2 but after i press apply it automatically changes it to 192.168.168.1 which is my ether3!!!

why?

Hi,
it’s better to set your configuration manually , quick set is not a good option